Impact mechanism.



J. H. BALDWIN.

IMPACT'MECHANISM. APPLICATION FILED MAR. 19. 1913.

1 159 4562, v Patented Nov. 9, 1915.

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BALDWIN ELECTRIC DRILL COMPANY OF NEW YORK.

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Specification of Letters Patent.

' JAMES nnwrrr BALDWIN, or nnenn'woon, 'nnw a'nnsnr, AssIeitoe homeson NEW roman. Y., n conronnrron Application filed March 19, 1913. Serial No. 755,294.

To all whom it may concern:

Be it known that I, James II. BALDWIN, a citizen of the United States, residing at Englewood, in the county-of Bergen and State of New Jersey, have invented certain new and useful Improvements in Impact Mechanism, of which the'following is a full, clear, and exact description.

The invention which forms the subject matter of this application relates to an improvement in an impact mechanism where- .111 the power is communicated to the blt,

hammer or other tool through the instrumentality of the air in the cylinder or casmg.

In devices of this character it not infrequently happens that the machine maynot be properly adjusted to deliver its blow so that during the operation the air partially escapes from the cylinder through the head thereof and, if no provision be made to take up the force of the blow, the piston will strike forcibly against the said head, resulting in damage and injury.

It is the object of this invention to overcome this defect.

Referring to the drawing wherein I show the preferred embodiment of. the invention,

- I Figure 1 shows a longitudinal section of an impact mechanism with my improvementsembodied therein. Fig, 2 shows a sectional view of the cylinder taken on line-;22 of Fig. 1, and looking in the direction" of the arrows. V y

In detail, the character 10 designates the outer casing of an impact mechanism, for example, a rock drill, having a cylinder 11 reciprocable therein.

To the head 12 of the cylinder is coimected'an arm or pitman 13', the latter connected to a motor-or other suitable power means '14 through the intermediate crank shaft 15,

and gears 16 and 1? connected to said crank shaft and motor respectively.

- Within the cylinder 11 i'sa piston 18 provided with a stem 19 which passes. through the lower head 20.. This piston freely movable in the cylinder, save for the resistance offered by the air when the piston moves toward either end thereof. The cylinder itself has free reciprocating motion in'the chamber 21, said motion being imparted thereto by the power means 14:, above referred to. The lower end of the chamber 21 is definedby the upper end of the member 22 which telescopes with the casing '10..

The piston-stem 19 passes through a pawld sk 23 located in the upper portion of the member 22. The grooves 24. (only one shown) cooperate with this disk 23 to give thepiston a slight rotation each time that the same is moved upward, the said disk being held stationary on theupward move ment by means of pawls (not shown) pro- ]B0t111gtherefromand engaging with a flanged disk 25 on the member22. The

stem 19 passes centrally through the member 22 and is .connectedat its lower end to-a Patented Nov. 9, i915.

chuck .26 which in turn makes suitable con-' 'with heads 33 while the other is provided with nuts 34:. Located between the nuts 34 and the ears 32 are resilient or cushioning means 35. I Y

Upon the cylinder 11.1 mount a sleeve 36 'provided with grooves 37. connecting the ports 38 in thesaid'cylinder. A handle 39 is employed to'operate the sleeve 36. The

' handle straddles the projection produced by one of the passages 37 and by means of the sleeve and, operating handle the flow of air through the passages can be regulated as 'deo sired, or stopped entirely. When out off e11 tirely perforations 40 in the cylinder may be made to register with corresponding perfo rations (not shown) in the sleeve. sleeve 36 is held against longitudinal movement by means of the screw-threaded sleeve 41, which forces the former against a shoul der at the opposite end of the cylinder. This mechanism just described I do not claim The.

herein as the same forms the subject matter of a separate application.

The operation of the device is as follows: In the 'positionsho wn in 1,-the cylinder. 11 is descending and the air therein above the piston, since the latter is above the air port 38, is' being compressed and'the power transmitted by the motor through the crank-shaft is being imparted' to the HO ton however will continue its downward movement owing to its momentum particularly so if the drill bit is out of contact with the object being drilled. This momentum may be so great as to force all the air out of the cylinder below the piston owing to the fact that it is impossible, on account of connections, to make the lower head air-tight. In this case, unless some provision be made, the piston would strike forcibly against the lower head resulting in'damage or injury, and whether or not any immediate injury or damage be done the constant pounding of the same in this manner will soon result in permanent injury to the impact mechanism as a whole. But with my improvements this cannot take place, since theenlargement 27 a on the piston stem 19 will contactwith the inwardly projecting flange 29 before the piston has had time to strike against the he'ad 23. The blow will be communicated from the member 22 to springs 35 and hence cushioned by the latter. i v a It is obvious that changes can be made in point of detail and'it is to be understood that the specific embodiment shown herein is simply the preferred form and that the principle can be embodied into other form without departing from the spirit and scope of this invention; What I claim is: H

1. In an impact mechanism having a body portion, a power driven reciprocatory cylinder, a piston movable axially in the cylinder and operatively connected therewith by piston and the ends of said cylinder, a stem connected to, said piston, in combination with a cushioning means on said body portion and engaged by said stem to prevent the piston from striking the lower end of the cylinder.

2. In an impact mechanism, a power driven reciprocatory cylinder, a piston movable axially in the cylinder and operatively connected therewith by the elastic body of air inclosed between the piston and the ends of said cylinder, a stem connected to said piston, and normally inoperative means independent of the power driven cylinder and ngageable by said stem upon an extreme Lovement of the piston to cushion the blow imparted to the said piston and stem.

3. In an impact mechanism having an outer casing, a power driven reciprocatory cylinder movable within said casing, a piston movable'axially in the cylinder and operatively connected therewith by the elastic body of air inclosed therein, a stem connected to said piston and passing through one end of-the cylinder, a member resiliently connected to the casing, and means on said stem to engage the said member to prevent the piston from making contact with said cylinder end.

.4. In a device of the classdescribed, a casing, a cylinder movable within said casing,

a piston movable axially within said cylinder and operatively connected therewith by the elastic body of air'inclosed therein, in combination with a cushioning mechanism comprising a member telescoping with the aforesaid casing and having a chamber therein through which the piston stem passes, resilient means normally holding the member in one extreme position, and means on said piston stem adapted to engage with said member to cushion the extreme forward stroke of the piston and stem.

In testimony whereof I aflix my signature I 'in the presence of two subscribing witnesses. the elastic body of air inclosed between the JAMES HEWITT BALDWIN. 

